The current project explores dynamic processes in spatial auditory perception. Specifically, it studies how representations of auditory space adapt to the auditory context defined by the preceding stimulation and by the listener's behavioral task. A series of behavioral experiments and computational modeling studies is proposed. The first tested hypothesis is that the contextual plasticity is influenced not only by the bottom-up factors, like the spatial distribution of the stimuli, but also by the top-down factors, for example, by the listener's concentration on the expected target locations and away from the distractor locations. This will be tested by comparing the plasticity observed when the listener is performing a task that requires specific distribution of spatial attention to plasticity observed when attention does not need to be focused. The second hypothesis is that the contextual plasticity is influenced by the spatial and temporal distribution of the stimuli. This will be tested by measuring plasticity observed in auditory scenes with various spatial and temporal distributions of distractor and target stimuli. The third hypothesis is that the anatomical locus of the contextual plasticity is at a central level of the auditory pathway where the underlying binaural cues are integrated into spatial percepts. This will be tested by evaluating the extend to which contextual plasticity induced by interaural temporal cues generalizes to interaural intensity cues for auditory localization, and vice versa. The results of these experiments will be evaluated in the context of the hierarchical model of auditory spatial perception proposed in the parent grant. Previous studies found that short-term plasticity in spatial auditory representations can be induced by sustained presentation of constant stimuli or by visual feedback to which the listeners align the auditory percepts. Other than that, spatial auditory perception was thought of as being static. The existence of contextual plasticity explored in this project is important because it suggests that auditory spatial representation is dynamic and that it changes continuously depending on the listener's task and on the auditory scene. Understanding how normal-hearing listeners adapt to the auditory context is critical, e.g., because similar plastic changes might take place in the central auditory processing of listeners with impaired auditory periphery. And designing prosthetic devices that predict and adapt to this neural plasticity might significantly improve the performance of such devices. This research will be done primarily in Slovakia at the Technical University of Kosice in collaboration with Norbert Kopco, as an extension of NIH grant #5R01 DC005778-03. [unreadable] [unreadable] [unreadable]